Method of treating fresh meat cuts

ABSTRACT

A process for treating and packing fresh meat cuts so that the fresh meat color of the cuts is retained over an extended period of time generally exceeding about twenty days, and microbial deterioration and spoilage of the meat is forestalled for a period which is at least as long as the meat cuts retain the fresh meat coloration. The process involves initially treating the meat with a three component chemical composition which contains a phosphate compound, an ascorbic acid or ascorbate and a citric acid or citrate. After the cuts are treated with the aqueous solution, they are packaged in a modified gaseous atmosphere which is predominantly carbon dioxide, but also contains oxygen in a certain critical ratio to the amount of carbon dioxide employed.

RELATED APPLICATIONS

This application is a continuation-in-part of my U.S. patent applicationSer. No. 806,609 filed on Dec. 9, 1985, now U.S. Pat. No. 4,683,139, andentitled "PROCESS FOR PREPACKING FRESH MEAT", which application is acontinuation-in-part of U.S. patent application Ser. No. 753,938 filedon July 11, 1985, now abandoned, and entitled "PROCESS FOR PRE-PACKINGFRESH MEAT".

BACKGROUND OF THE INVENTION

This invention relates to meat treating and prepacking processes, andmore particularly, to methods for chemically treating meat and packagingor storing meat so that the meat remains in an unspoiled, freshappearing condition over an extended period of time.

BRIEF DESCRIPTION OF THE PRIOR ART

In order to control bacterial spoilage in meat, it has been proposed touse a relatively high or enhanced level of carbon dioxide to preservethe meat as it is containerized by the packer, and for the purpose ofminimizing microbial growth and extending the shelf life of the meat.However, the depletion of oxygen, and the presence of a highconcentration of carbon dioxide accelerates the loss of the desirablered color in the meat, and the progression of bone discoloration, andthese factors reduce the shelf life which characterize meat prepacked inthis way.

In some systems, particularly in European markets, the gaseousenvironment used in packing fresh meat cuts has included a high level ofoxygen in order to maintain the red coloration of the meat indicative offreshness. A high level of oxygen, however, accelerates oxidativerancidity reactions which cause the development of both an undesirableodor in the meat, and an undesirable oxidative flavor.

I have now determined that the optimization of fresh meat prepackingsystems can only be realized where the concurrently confronted problemsof bacterial spoilage, meat discoloration, bone discoloration, oxidativerancidity and variation the pH of the meat are resolved, or at leastsatisfactorily alleviated.

U.S. Pat. No. 3,154,421 discloses that the desirable bright red freshmeat color can be maintained for about a one week period in the case offresh meat packaged in air (about 21 percent O₂) by treating the meatwith a mixture of phosphate salts, ascorbic acid, or alkali metal salts,and a sequestering agent, such as citric acid. This patent does notsuggest how the shelf life of the fresh meat might be yet furtherextended, nor does it provide any indication of the effect which wouldbe realized if meat treated with the described chemicals were packed ina controlled, modified gaseous atmosphere containing a substantialamount of carbon dioxide as compared to air. The patentees state that"the natural pH" of the meat is about 6.2.

BRIEF DESCRIPTION OF THE PRESENT INVENTION

The present invention is a method for the centralized prepacking offresh cuts of meat which have an excellent extended shelf life and aresuitable for display at the point of retail sale in consumer sizedpackages. I have determined that there is a wide and unpredictablevariation in the pH which characterizes fresh pork loins derived, atrandom, from freshly slaughtered hogs. Pork loins also vary considerablyin the flavor and other organoleptic properties exhibited by the loinsafter extended periods of storage at near freezing temperatures. Theunpredictability of these various properties, and the pH variation whichexists, influencing as it does, the reaction of the meat to packagingconditions over extended periods of time, results in a lack ofconsistency of quality which is discouraging to consumer selection andpurchase. In other words, fresh cuts, such as pork chops, thoughoriginated at the same time from the same packer, display and exhibit atthe time of sale, very substantial differences in appearance, taste,odor and exuded purge or other properties from one chop to the next--orat least from one package to the next.

I have further determined that the pH value of fresh meat is related tothe extent to which the meat retains the bright red color associatedwith freshness, and which is a highly desirable characteristic from thestandpoint of consumer acceptance. Thus, I have found that pork chopshaving a pH which is lower than about 5.7 tend to become discolored byturning a dull and unsightly brown after from seven to fourteen days inthe package and during storage. The chops having a pH higher than about5.7 on the other hand, retain the bright red color indicative offreshness much better. This fresh meat color difference is substantiallymore pronounced where the chops are packaged in a modified atmospherewhich contains significantly more carbon dioxide that is present in air.A modified gaseous atmosphere of this type is desirable for packagingfresh pork, because the enhanced level of carbon dioxide suppressesmicrobial activity which causes spoilage of the meat. This controlled ormodified atmosphere packing thus extends the effective microbial shelflife of the meat over that attainable when the meat is packed in air andhigh oxygen atmospheres.

Although I have observed and confirmed the described variation in colorlevel and stability to be associated with differences in the pH ofvarious cuts of fresh pork, it is quite burdensome economically toundertake to test all freshly slaughtered animals, or the cuts derivedtherefrom, to determine pH before undertaking to package only therelatively high pH cuts so that the consumer can expect consistentlyexcellent color and quality in all such cuts.

It is against the background of the described observations of the effectof pH, and the wide variation in the organoleptic and other propertiesof fresh meat, that the present invention has evolved. The presentinvention permits fresh pork, beef and lamb meat of consistent highquality and extended shelf life to be economically pre-packaged at acentral location without the necessity of a cut-by-cut oranimal-by-animal analysis of pH and other properties before commencingthe packing procedure.

Broadly described, the packing method of the invention comprisesinitially treating fresh cuts of pork, beef or lamb with an aqueoussolution which effectively maintains the red coloration of the meat fora period well exceeding 14 days by retaining the heme iron in a reduced(ferrous) state, and retarding or precluding oxidation reactions by botha reducing activity and a sequestering action by whichoxidation-promoting metallic ions are sequestered or chemically bound. Atreating solution employed for this purpose is a three-component aqueoussolution which includes (a) an alkali metal salt of one or more ofcertain phosphate compounds, (b) a reducing compound selected from thegroup consisting of ascorbic acid, isoascorbic acid, the alkali metalsalts of these acids, and reductic acid, and finally, (c) a sequesteringor chelating agent, such as citric acid, tartaric acid, and ethylenediamine tetraacetic acid or the alkali metal salts thereof.

Several methods of application of the buffer solution to the fresh meatcuts can be utilized, including pumping, marinating and spraying. Ingeneral, a sufficient amount of the aqueous buffer solution is placed onand into the meat that the treated product will contain the activecomponents in concentrations such that from about 0.1 weight percent toabout 2.0 weight percent of the phosphate compound is included, fromabout 0.01 weight percent to about 0.30 weight percent of the reducingcompound is included, and from about 0.01 weight percent to about 0.30weight percent of the sequestering or chelating agent is included.

After the fresh cuts have been treated with the buffer solution, theyare placed in a package which can be sealed to be relatively gas tight.Incorporated within the package and over the meat cuts is a gaseousatmosphere which contains from about 20 to about 80 percent of carbondioxide and from about 2 to about 30 percent of oxygen. The remaininggas present consists essentially of nitrogen. The specifiedconcentrations of gases are based upon mole percent of the gas presentin the mixture.

Finally, the packaged meat is preferably stored and transported at atemperature of 34°±2° F., and is displayed and sold at retail at atypical meat case temperature of 38°±2° F.

An important object of the invention is to provide a process fortreating and packing fresh meat so that the meat will remain in anattractive, substantially odor-free and palatable condition over anextended shelf life after the meat has been packed according to themethod of the invention, and shipped from the meat packer to itsdestination.

A further object of the invention is to stabilize the pH of fresh porkcuts at a pH value which is optimum for packing, shipment and display atthe point of retail sale, and for the purpose of preventing loss of theattractive red or pink fresh meat coloration.

Yet a further object of the present invention is to provide a processfor treating and packing fresh pork, beef and lamb cuts so that the meatis maintained in an attractive, unspoiled condition over an extendedperiod of time.

Another object of the invention is to provide a method of prepackingfresh meat cuts which eliminates the necessity for repackaging orhandling or processing of any type by a retailer after receiving thepackaged meat from the meat packer.

Another object of the invention is to process fresh meat so that it canbe shipped and stored to consistently exhibit at least 20 days shelflife with retention of good quality and good color over at least thisperiod of time when packaged in a selected modified atmosphere which isrelatively high in CO₂.

An additional object of the present invention is to provide a new methodfor packaging fresh meat cuts, such as pork chops, beef and lamb chopsso that the meat does not become discolored, and the microbial activityin the meat cuts is maintained at acceptable levels over extended timeperiods adequate to facilitate display and sale of the meat to theconsumer without further treatment or alteration of the packaging.

Another object of the invention is to stabilize and homogenize certainconsumer sensitive characteristics of fresh meat, so that fresh meatcuts having inherently variable properties can be made, by a singletreatment and procedure, to display uniform, highly desirable propertiesover extended shelf life periods.

A further object of the invention is to extend the color shelf-life ofrelatively low pH pork cuts to an extent such that the cuts retain anexcellent fresh color for a time period substantially equivalent to thebest attainable microbiological shelf-life.

Yet a further object of the invention is to enhance the organolepticproperties of fresh meat, including, for example, pork, beef and lamb.

Another object of the invention is to eliminate the necessity forpretesting fresh pork cuts for pH in order to know which of such cutscan be prepacked and successfully sold at retail outlets more than aboutfourteen days after such prepacking.

A further and more specific object is to reduce the percent of purgeexuded from fresh meat cuts over extended storage times.

Another relatively specific object of the invention is to retard theprogression in fresh pork, beef and lamb meat of oxidative ranciditycausing off-odor and off-flavor.

Additional objects and advantages will become apparent as the followingdetailed description of a preferred embodiment of the invention is readin conjunction with the accompanying drawings which illustrate apreferred embodiment of package developed in the course of practicingthe process of the present invention, and which also graphically portraythe results of certain tests which were performed to confirm theefficacy of the invention.

GENERAL DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a compound package useful inpracticing the process of the present invention.

FIG. 2 is a graph showing a type and duration of meat surface color ofpork chops having a pH of about 5.5 and about 5.8 when packed in amodified gaseous atmosphere without any type of pretreatment.

FIGS. 3 and 4 are graphs portraying various properties displayed by porkchops having a pH of about 5.8 both where the chops have been pretreatedwith the buffer solution of this invention, and where no pretreatmenthas been carried out.

FIGS. 5 and 6 are graphs similar to FIGS. 3 and 4, but depicting theresults obtained using untreated and treated chops, respectively, havinga pH of about 5.5.

FIG. 7 is a graph illustrating how the bacterial count and odor ofuntreated pork chops of pH 5.5 are affected by extended storage in ahigh CO₂ modified atmosphere as compared to air.

FIG. 8 is a graph similar to FIG. 7, except showing results of microbialand odor tests carried out using pork chops having a pH of about 5.8.

FIGS. 9-15 are graphs which show the results obtained when a number ofcharacteristics of pork chops having pH values in the range of fromabout 5.5 to about 5.8 (after pretreatment)are observed or measuredafter pretreating the chops in various ways and then packing them in amodified atmosphere over a period of twenty-eight days.

FIGS. 16-23 are graphs similar to those shown in FIGS. 9-15, but basedupon tests carried out using pork chops having pH values in the range offrom about 6.2 to about 6.6 (after treatment).

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

The process of the present invention broadly includes two aspects.First, the fresh meat--generally cuts such as pork loins or pork chopsor steaks or lamb chops--is treated with an aqueous buffer solution soas to incorporate certain active chemicals. This pretreatment then aidsin the maintenance of desirable color, the prevention of undesirableoxidative reactions, the enhancement of organoleptic properties and theoverall preservation of the meat over an extended period of time whenthe pretreated meat is stored or packed in a certain modified gaseousatmosphere.

After treatment with the aqueous buffer solution, the second major phaseof the process of the invention involves packing the treated meat cutsin a modified gaseous atmosphere which contains oxygen and a substantialamount of carbon dioxide. This gaseous mixture, which containssubstantially more carbon dioxide than is found naturally in air, hasbeen found to substantially retard bacterial spoilage, and thussubstantially extend the microbial shelf life of the meat.

The aqueous solution used in the initial step in the process of theinvention includes three active constituents. The first of these is aphosphate compound selected from the group consisting of alkali metalorthophosphates, pyrophosphates, tripolyphosphates andhexametaphosphates. Phosphate compounds in which the cation is sodium orpotassium are preferred. The amount of the phosphate compound employed,based on the total weight of the cut after treatment, is from about 0.1to about 2.0 weight percent, and is preferably from about 0.2 to about0.5 weight percent. The concentration of the phosphate compound in theaqueous solution will vary according to the manner in which the buffersolution is applied to the meat. Thus, for example, and as will behereinafter explained in greater detail, where the buffer solution isapplied to the meat by injection or pumping, a relatively larger amountof the aqueous buffer solution remains in the meat than is incorporatedtherein when a marinating process is used. For this reason, theconcentration of the active ingredients, including the phosphatecompounds, can be relatively lower in the aqueous buffer solution sopumped or injected.

The second active ingredient in the aqueous buffer solution is areducing agent or compound. The preferred compounds having reducingactivity and which are acceptable as a food additive are ascorbic acidand isoascorbic acid, and the alkali metal salts of these acids. Thepotassium and sodium salts are preferred. Reductic acid can also beutilized. The reducing agents used in the aqueous buffer solutionfunction to retain the heme iron in the meat pigment in the ferrousstate. The meat therefore tends to retain its red color, and to have afresh appearance over an extended time period. The reducing agent alsofunctions to retard or inhibit oxidative reactions resulting inrancidity, and in the production of TBA-reaction products, such asmalonaldehyde.

The amount of reducing compound employed can vary over a wide range, butin the case of the preferred ascorbic acid, isoascorbic acid and thealkali metal salts of these acids, it is preferred that a concentrationof from about 0.01 to about 0.3 weight percent be incorporated in themeat. The most preferred amount of the reducing agent utilized is fromabout 0.02 weight percent to about 0.05 weight percent.

The third active component of the aqueous buffer solution is asequestering or chelating agent which is a compound capable of tying upor bonding certain metal ions present in low concentrations in the meat,and which function as undesirable prooxidants. Typical of such metalions are iron, zinc and copper. Several effective sequestering agentsare known to chelate or form complexes with these metal ions. Thosewhich are preferred in the case of the present invention are, however,citric acid, tartaric acid, ethylenediaminetetracetic acid, and thesodium and potassium salts thereof. The quantitative amount of thesequestering agent which is incorporated in the treated meat is fromabout 0.01 to about 0.3 weight percent. The amount of the sequesteringagent which is preferably utilized is from about 0.01 weight percent toabout 0.05 weight percent based, of course, on the total weight oftreated meat. Citric acid is the preferred sequestering compound.

In treating fresh meat cuts with the described three-component treatingsolution, the treatment of the meat can be effected in several ways.Larger cuts or primal cuts are treated by pumping or injecting the meatwith the buffer solution.

If the primal cuts are to be further subdivided to produce smaller cuts,the primal cuts need not be treated and these secondary cuts arepreferably marinated in the buffer solution. The secondary cuts can,alternatively, be sprayed with the buffer solution.

The described treatment with the three-component aqueous buffer solutioncan be especially beneficially employed for treating fresh meat cutshaving a pH of between about 5.2 and about 5.7 because in the case ofthese relatively low pH cuts, I have determined that without suchtreatment they will become discolored relatively soon in an enhanced CO₂environment. Cuts which have a pH above about 5.7, on the other hand,appear to retain their fresh meat color over an extended period of timewhich is substantially coextensive with the microbiological shelf lifeof extended duration achieved by packing the meat in an enhanced carbondioxide gaseous environment.

Despite this marked difference in the relationship of the variouscolor-determining pigments to the parameters of pH and the particulargaseous environment in which the meat cuts are packed, I have determinedthat pretreatment of the meat carried out in accordance with the presentinvention makes it unnecessary to engage in expensive, time consumingpretesting to identify cuts which, by reason of a characteristically lowpH, are unsatisfactory for extended storage followed by retail saledisplay.

I have further determined that such pretreatment is especially valuableand advantageous because of the unexpectedly wide and unpredictablevariations in the pH of fresh pork cuts taken from animals raised undersimilar circumstances and in the same environment. Such pH variation isstrikingly shown by the results of a series of pH measurement testsconducted at plant level on freshly cut pork loins over a period ofabout two months. The results of these tests to determine the pH offresh loins showed, as tabulated in Table I, that the amount of thetested loins having a pH greater than about 5.7 (below which fresh meatcolor stability cannot be expected) varied unpredictably from 22.2percent of the loins of animals slaughtered and tested on one day, up toabout 98.1 percent of the loins derived from animals slaughtered andtested about four days later.

                  TABLE I                                                         ______________________________________                                                             Total Loins                                                                              Percent Loins                                                      Having pH  Having pH                                     Test     Total Loins Greater than                                                                             Greater Than                                  Date     Sampled     5.7        5.7                                           ______________________________________                                        7/03/85  100         42         42.0                                          7/16/85  100         24         24.0                                          7/17/85  100         45         45.0                                          7/18/85  100         72         72.0                                          7/22/85  100         68         68.0                                          7/23/85  100         69         69.0                                          7/24/85  270         140        51.9                                          7/25/85  210         95         45.2                                          7/26/85  100         33         33.0                                          8/13/85  100         61         61.0                                          8/23/85  152         72         47.3                                          8/23/85  135         30         22.2                                          8/23/85  140         58         41.4                                          8/23/85  140         58         41.4                                          8/27/85   52         51         98.1                                          8/27/85   65         58         89.2                                          9/04/85  100         26         26.0                                          9/09/85  100         51         51.0                                          9/13/85  100         37         37.0                                          ______________________________________                                    

As will be hereinafter shown, pretreatment with the aqueous buffersolution of the present invention effectively extends the color shelflife of the low pH loins and chops. Such pretreatment also enhances andrenders substantially consistent with such parameters observed in thehigher pH chops, other consumer sensitive parameters, such as theorganoleptic properties of the meat (taste, odor, etc.). It also usuallyreduces the purge from both the relatively high pH chops and therelatively low pH chops.

An important significance and value of this determination is that by theuse of the buffer solution pretreatment, it becomes unnecesary topretest each pork loin or pork chop in order to be certain that,regardless of the type of gaseous atmosphere in which the chop ispackaged, it will not develop an unacceptable color in a short time as aresult of having a relatively low pH. All of the freshly slaughteredanimals, or the cuts derived therefrom, can be treated with thetreatment solution prior to prepackaging in the modified atmosphere, andour experimentation and results indicate that when such treatment iscarried out, the treated chops stored at 32°-34° F. in an enhanced(modified) carbon dioxide gaseous atmosphere will have a color andmicrobiological shelf life exceeding twenty-one days. Moreover, all ofthe organoleptic properties are enhanced and rendered substantiallyconsistent, as compared to fresh meat cuts which have not undergone suchpretreatment.

When the preferred active ingredients of the treating solution areemployed, and are used in the ranges described, the aqueous solutionutilized will have a pH of from about 5.0 to about 8.0. Where thetreating solution requires a slight elevation in pH to bring it into thedescribed range, a very small amount of sodium carbonate or sodiumbicarbonate can be used for this purpose, although such is generally notneeded. Preferably, the aqueous treating solution is made up to have apH of between 6.0 and 7.0. This solution of this preferred pH willgenerally be effective to slightly elevate the pH of cuts to which thebuffer solution is applied.

The cuts which have been treated with the aqueous buffer solution arenext packed in a gaseous environment which has been optimized to includea sufficient amount of carbon dioxide to provide an effectivebacteriostatic effect on aerobic psychrotrophic bacteria, and which alsocontains a sufficient amount of oxygen to form oxymyoglobin in the meat.This latter effect acts in conjunction with the color effect of theaqueous treating solution to maintain the fresh red color of the meatover an extended period of time. The gaseous environment used to meetthe described objectives contains from about 20 to about 80 percentcarbon dioxide and from about 2 to about 30 percent oxygen. The balanceconsists essentially of nitrogen.

The amount of carbon dioxide which is preferably present in the gaseousmixture used in packing the treated cuts is from about 30 percent toabout 60 percent, with about 50 percent being optimum. The amount ofoxygen in the gaseous mixture is most suitably from about 10 percent toabout 25 percent, with about 15 percent to about 21 percent being themost preferred oxygen concentration for treated meat in general. Thecomposition of the gaseous atmosphere in the package will graduallychange with passing time in storage or shipment as the gases areabsorbed by the meat. Typically, the amount of nitrogen in the gaseousmixture will slightly increase, and the carbon dioxide content willslightly decrease.

Various types of packaging can be employed, but I prefer to employ acompound package of the type having a plurality of internal packageswithin an external package.

Cuts which have been treated with the described aqueous solution in theway discussed are illustrated and denominated by reference numeral 10 inFIG. 1 of the accompanying drawings. These treated cuts 10 are placed onstyrofoam trays 12, each of which carries a soaker pad 13 in the bottomfor absorbing exudate and juices from the meat cuts. Each styrofoam tray12 is then passed into an environment where a selected gaseousatmosphere is provided around the meat cut as the styrofoam tray isclosed with a gas permeable film of synthetic resin. The gaseousatmosphere around the meat and over the styrofoam tray 12 at this pointin the process preferably contains oxygen and carbon dioxide in theconcentrations hereinbefore described.

After formation of the primary package using the procedure described inthe cited co-pending application, several of the small primary packages16 which, as there explained, are preferably of case-ready configurationand size, are positioned in a larger container to form a compoundsecondary package 18. A number of the styrofoam trays 12 are placed on alarger, thermoformed secondary tray 20. The secondary tray 20 is thensubjected to a sealing process in which a gas impermeable film 22 ofsynthetic resin is used for enclosing all of the smaller primarypackages 16. In the course of sealing the secondary tray 20, the air isinitially evacuated from this compound package, and is then replacedwith a gaseous mixture which contains oxygen and carbon dioxide in thepreviously described concentrations. In evacuating air from thesecondary tray, a vacuum in excess of about 15 inches of mercury isavoided so that the gas permeable films of the primary packages 16 willnot burst or excessively wrinkle. As a result of the placement of thedescribed gaseous mixture within the gas impermeable sealing film 22 ofthe secondary tray 20, the pressure over the primary packages isreturned to approximately atmospheric pressure.

Upon completion of the packing, the packages are preferably maintainedat a temperature of 34°±2° F. during storage and transportation.Maintenance of this temperature greatly assists in the extension of theshelf life without microbial spoilage. After arrival at the point ofretail sale, the small primary packages are removed and are displayed atabout 38° F.

The treatment of the meat cuts with the aqueous treatment solution,followed by packing them in packages in which the described amounts ofcarbon dioxide and oxygen are included, yields several advantages notattained in prior art packing methods. First, the bacteriostatic effectof the carbon dioxide controls the growth of psychrotrophicaerobes--meat spoilage bacteria. The presence of at least 2 percentoxygen and of the reducing compound in the treating solution maintainsthe red color of the meat so that the meat has a fresh appearance.Without this oxygen content, the high level of carbon dioxide presentwould cause the development of a browngrayish color in the meat andsevere bone discoloration in a relatively short time, making the meatunattractive to the consumer. Further, the development of undesirableoxidative off-flavor resulting from oxidative rancidity in the meat isretarded by the reducing and sequestering substances in the treatingsolution.

Another advantage of the process of the present invention is that the pHof the meat cuts can be adjusted upwardly by the use of the treatingsolution, and the adverse effect of a high level of carbon dioxide onthe color of relatively low pH meat can be minimized through pHelevation upon treatment with the solution. Thus, for example, thequality of pork chops or other pork cuts of low pH (pH 5.6 or lower),which cuts constitute a large portion of the total production (see TableI), can be upgraded, and the quality consistency of the product overextended periods of time can be assured. As pointed out above, it is noteconomically practical to pH test every one of the fresh cuts, but it isneither difficult, time consuming, nor expensive to pretreat all of themwith the buffering solution of the present invention in order toovercome color loss upon packing them in a modified atmosphere.Moreover, the application of the treating solution to even therelatively high (greater than pH about 5.7) pH cuts improves theorganoleptic properties of these chops and reduces purge loss.

Without described buffer solution treatment, discoloration of the meatand bone become limiting factors in the shelf life of pork chops storedin an atmosphere characterized by a sufficiently high level of carbondioxide to prevent bacterial spoilage. The ability to maintain the colorof the meat, despite the presence of a substantial amount of carbondioxide, is due both to the inclusion in the buffer solution of reducingagents which retain the heme iron in the meat pigment in the ferrousstate, and to the presence of at leats 2 percent, and preferably atleast 15 percent oxygen in the gaseous atmosphere in which the meat ispacked.

EXAMPLE 1

A number of tests were carried out to determine the effect of treatingpork chops with the aqueous buffer solution, followed by packing thechops in several types of gaseous environments, followed by storing thechops for extended periods of time at 34° F. Each of the chop samplesused in the tests was about one-half inch thick, and was cut to weightabout one-quarter pound by removal of most of the fat so that the chopwas close trimmed. Periodically during the storage, the chops wereexamined to evaluate the pH of the chops, the progression of meatdiscoloration, the progression of bone discoloration and the overallappearance. The chops were also periodically examined for thedevelopment of oxidative rancidity (TBA) and for off-odor.

In these tests, 22 pork chops were cut from a first pork loin and 20pork chops from a second pork loin. The chops from each loin were thendivided into groups which would represent storage period time incrementsat which observations of the chops in the group would be made. The porkchops in each of the groups were chops cut from the parent loin atsubstantially the same locations. The chops in each group were, forpurposes of reporting the test results, identified and tabulated in thetest results as Chops 1, 2, 3, and 4.

In each group of chops, the chops denominated No. 1 and No. 3 were thecontrol samples, and were not subjected to buffer solution treatment.The No. 2 and No. 4 pork chops in each of the groups were marinated inthe buffer solution for thirty seconds. The aqueous buffer solutionutilized for treating the No. 2 and No. 4 pork chops contained about10.3 weight percent tetrasodium pyrophosphate, about 1.72 weight percentof sodium erythorbate and about 3.4 weight percent of citric acid. Themarination treatment resulted in an average increase in the weight ofthe chops of about 3 percent.

The No. 1 and No. 2 chops in each group, constituting, as describedabove, one control sample and one chop treated with the described buffersolution, were each placed in a package in a gaseous atmosphere whichcontained 40 percent carbon dioxide, 25 percent oxygen and 35 percentnitrogen. Chop Nos. 3 and 4 in each group were each placed in a packagewhich contained 40 percent carbon dioxide, substantially no oxygen and60 percent nitrogen. These two gaseous atmospheres used for packing theseveral samples are shown in Table II.

                  TABLE II                                                        ______________________________________                                        Gaseous Atmosphere in the Test Packages, Percent                                       Chop Samples                                                                            Chop Samples                                                        No. 1 & No. 2                                                                           No. 3 & No. 4                                              ______________________________________                                        CO.sub.2   40.0        40.0                                                   O.sub.2    25.0        0.0                                                    N.sub.2    35.0        60.0                                                   ______________________________________                                    

Table III shows the manner in which the gaseous atmosphere changed inits composition after the packages had been stored at 34° F. for aperiod of 34 days, during which time the chops were periodically tested.

                  TABLE III                                                       ______________________________________                                        Gaseous Composition in the Test Packages After Storage                        at 34° F., Percent                                                              Chop Samples                                                                            Chop Samples                                                        No. 1 & No. 2                                                                           No. 3 & No. 4                                              ______________________________________                                        CO.sub.2   26.0        24.0                                                   O.sub.2    27.0        2.0                                                    N.sub.2    47.0        74.0                                                   ______________________________________                                    

At approximately weekly time intervals, the pork chops in the severalsets were tested for meat discoloration, bone discoloration and overallappearance. The results of these tests are set forth in Tables IV, V andVI, respectively.

                                      TABLE IV                                    __________________________________________________________________________    Meat Discoloration*                                                                   Loin No. 1 Samples                                                                            Loin No. 2 Samples                                            Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                      Days at 34° F.                                                                 No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                                                             No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                     __________________________________________________________________________     1      7   7   --  --  --  --  --  --                                         6      5   6   1   2   6   6   3   6                                         13      5   6   1   2   4   5   1   4                                         20      4   5   1   2   4   6   1   2                                         27      2   4   1   1   3   5   1   1                                         34      2   4   1   1   2   4   1   1                                         __________________________________________________________________________     *(7) No surface discoloration                                                 (6) Trace discoloration                                                       (5) Slight discoloration                                                      (4) Moderate discoloration                                                    (3) 1/4 discoloration                                                         (2) 1/2 discoloration                                                         (1) Total surface discoloration                                          

                                      TABLE V                                     __________________________________________________________________________    Bone Discoloration**                                                                  Loin No. 1 Samples                                                                            Loin No. 2 Samples                                            Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                      Days at 34° F.                                                                 No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                                                             No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                     __________________________________________________________________________     1      -   -   -   -   -   -   -   -                                          6      ++  -   ++  -   ++  -   ++  -                                         13      +++ -   +++ -   +++ -   +++ -                                         20      +++ -   +++ -   +++ -   +++ -                                         27      +++ ++  +++ -   +++ -   +++ -                                         34      +++ ++  +++ +++ +++ ++  +++ +++                                       __________________________________________________________________________     **None                                                                        Slight                                                                        Moderate +                                                                    Total ++                                                                 

                                      TABLE VI                                    __________________________________________________________________________    Overall Appearance***                                                                 Loin No. 1 Samples                                                                            Loin No. 2 Samples                                            Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                      Days at 34° F.                                                                 No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                                                             No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                     __________________________________________________________________________     1      6   7   --  --  --  --  --  --                                         6      4   6   1   3   4   6   3   6                                         13      3   6   1   3   3   6   1   4                                         20      3   5   1   2   3   6   1   2                                         27      2   4   1   1   3   5   1   1                                         34      1   3   1   1   2   4   1   1                                         __________________________________________________________________________     ***(7) Extremely desirable                                                    (6) Moderately desirable                                                      (5) Desirable                                                                 (4) Slightly undesirable                                                      (3) Moderately undesirable                                                    (2) Undesirable                                                               (1) Extremely undesirable                                                

The test results set forth in Table IV show that Chops No. 1 and No. 2,which were packaged in a gaseous mixture containing about 25 percentoxygen and about 40 percent carbon dioxide, showed only slight meatdiscoloration after 13 days of storage. The No. 2 chops which had beentreated with the buffer solution, retained their fresh color longer thandid No. 1 chops, and even after the 27th day showed only moderatediscoloration. By this time, about one-half of each No. 1 chop hadbecome discolored.

The tests further showed that marination in the buffer solution of theNo. 4 pork chops from Loin Sample No. 1 did little to retarddiscoloration in the meat where the gaseous atmosphere into which thesechops were placed contained the same 40 percent level of carbon dioxideas in the case of the No. 1 and No. 2, pork chops, but containednegligible oxygen. In the case of the No. 3 and 4 pork chops derivedfrom Loin Sample No. 2, the No. 4 chops which had been pretreated with abuffering solution did become discolored more slowly, even when storedin the oxygen-free gaseous atmosphere. This appears to demonstrate thattreatment with the buffer solution, while functioning far less thanoptimally unless coupled with the use of the described preferred gaseousmixture, nevertheless does have some effect in retarding meatdiscoloration in the presence of a high concentration of carbon dioxidewith very little oxygen present. Table IV clearly shows, nevertheless,that a more advantageous mode of processing entails pretreatment withthe buffer solution, followed by packing of the chops in a package whichcontains significant oxygen. This is confirmed by the results obtainedin testing the No. 2 pork chops from both of the pork loins. These chopswere pretreated with the buffer solution as described, then packed inthe oxygen and carbon dioxide-containing atmosphere.

Table V shows the result of examining bone discoloration in pork chopstreated and packed in the same way as the chops referred to in Table IV,where the meat discoloration results are reported in tabular form. Itwill be noted that in the case of the No. 2 and No. 4 chops, which weremarinated in the buffer solution before packing, bone discoloration wasnegligible for a period of 20 days, and that even after 27 days, bonediscoloration was not significant in the case of these pretreated chopsfrom each of the two loin samples. By contrast, the bones of the No. 1and No. 3 chops from each of the two loin samples became, in each case,totally discolored after only 13 days. The bone color desideratum doesnot appear to be as adversely affected by packing in a gaseousatmosphere which is very low in oxygen as does the meat colordesideratum.

Table VI undertakes to evaluate the overall appearance of the chops fromeach of the two loins upon periodic observations. Again, the importanceof the presence of a small amount of oxygen in the gaseous mixture inwhich the chops are packed is apparent from tabulated results. The No. 1and No. 2 chops from each of the loins are unquestionably of betterappearance over extended periods of time, and at virtually all testintervals, than the No. 3 and No. 4 chops which were packed in anoxygen-free gaseous environment. The test results further demonstratethe importance of premarination with the aqueous buffer solution,because in every instance of equivalent gaseous atmospheres used inpacking of the chops, those chops which were premarinated show a betteroverall appearance than those not receiving this treatment. The bestresults occurred in the case of the No. 2 chops from each of the loinsamples, and these buffer solution-treated chops, packed in anoxygen-CO₂ gaseous atmosphere, continued to have a desirable appearancefor at least 20 days.

At the intervals of observation and measurement described, the severalpork chops derivedfrom the two loins were also tested to determine thesurface pH of the cuts. These results are tabulated in Table VII.

                                      TABLE VII                                   __________________________________________________________________________    Meat Surface pH                                                                       Loin No. 1 Samples                                                                            Loin No. 2 Samples                                            Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                      Days at 34° F.                                                                 No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                                                             No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                     __________________________________________________________________________     1      5.31                                                                              5.46                                                                              --  --  --  --  --  --                                         6      5.42                                                                              5.59                                                                              5.45                                                                              5.60                                                                              5.42                                                                              5.60                                                                              5.42                                                                              5.61                                      13      5.50                                                                              5.68                                                                              5.51                                                                              5.64                                                                              5.47                                                                              5.64                                                                              5.48                                                                              5.68                                      20      5.49                                                                              5.69                                                                              5.52                                                                              5.72                                                                              5.48                                                                              5.67                                                                              5.49                                                                              5.66                                      27      5.54                                                                              5.71                                                                              5.54                                                                              5.68                                                                              5.47                                                                              5.66                                                                              5.50                                                                              5.72                                      34      5.46                                                                              5.65                                                                              5.38                                                                              5.54                                                                              5.36                                                                              5.53                                                                              5.36                                                                              5.51                                      __________________________________________________________________________

It will be perceived from the results in Table VII that treatment withthe buffer solution is generally effective to elevate the pH of chopstaken from adjacent locations in the respective loins by a pH incrementof about 0.15. It is further apparent by correlating the pH values ofthe several chops after the test periods of storage at 34° F. that thosechops which have a pH of over 5.6 generally retain a desirable color ofboth the meat and bone for a longer period of time.

In Table VIII, TBA (oxidative rancidity) values for the chops aretabulated as determined at the periodic times of testing andobservation. In determining the TBA value of a meat cut, a distillatefrom the cut is treated with a standard mixture of 2-thiobarbituric acidand glacial acetic acid to develop a color. This color is an indicatorof the rancidity level in the meat. In general, a TBA value above about1.5 is indicative of the onset of rancidity, and an undesirable odor canbe detected.

                                      TABLE VIII                                  __________________________________________________________________________    TBA Oxidative Rancidity Values                                                        Loin No. 1 Samples                                                                            Loin No. 2 Samples                                            Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                      Days at 34° F.                                                                 No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                                                             No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                     __________________________________________________________________________     1      0.19                                                                              0.16                                                                              --  --  --  --  --  --                                         6      0.22                                                                              0.13                                                                              0.17                                                                              0.11                                                                              0.19                                                                              0.10                                                                              0.23                                                                              0.13                                      13      0.30                                                                              0.23                                                                              0.31                                                                              0.22                                                                              0.31                                                                              0.22                                                                              0.39                                                                              0.33                                      20      1.70                                                                              0.45                                                                              1.10                                                                              0.27                                                                              0.53                                                                              0.33                                                                              0.52                                                                              0.36                                      27      4.40                                                                              0.64                                                                              1.80                                                                              0.41                                                                              1.20                                                                              0.38                                                                              0.47                                                                              0.30                                      34      8.60                                                                              1.40                                                                              2.70                                                                              0.56                                                                              0.81                                                                              0.28                                                                              0.58                                                                              0.30                                      __________________________________________________________________________

The values set forth in Table VIII clearly show the advantage oftreating the chops with the aqueous buffer solution to control thedevelopment of oxidative rancidity in the meats, regardless of whetherthe atmosphere in which the chops are packaged is high in oxygen. Thisis shown by the advantage in this respect of the No. 2 and No. 4 chopsover the control chops (Chops No. 1 and No. 3).

Table IX reports the result of odor tests carried out at the periodictesting times utilized in the examination of the other test parameterspreviously described. An off-odor indicative of rancidity was at leastmoderately detectable in the case of all of the tested chops after 27days in storage at 34° F. The chops which had been marinated in thebuffer solution, however, had, at worst, only a slightly detectable odorafter 20 days in storage.

                                      TABLE IX                                    __________________________________________________________________________    Off-Odor*                                                                             Loin No. 1 Samples                                                                            Loin No. 2 Samples                                            Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                                                              Chop                                      Days at 34° F.                                                                 No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                                                             No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                     __________________________________________________________________________     1      4   4   --  --  --  --  --  --                                         6      4   4   3   3   4   4   4   4                                         13      3   3   2   2   4   4   4   4                                         20      2   3   2   3   3   4   4   4                                         27      1   2   1   1   2   2   2   2                                         34      1   1   1   1   1   2   1   1                                         __________________________________________________________________________     *(4) No detectable offodor                                                    (3) Slightly detectable                                                       (2) Moderately detectable                                                     (1) Very strong offodor                                                  

The described test results clearly show that significant improvements inthe appearance and in the shelf life quality of fresh pork cuts isattainable through practice of the present invention. The highlyeffective procedure involves the coupling of the buffer solutionpretreatment with packing of the treated meat cuts in a gaseousenvironment which contains both oxygen and at least 20 percent carbondioxide.

EXAMPLE 2

Tests were carried out to determine the effect on meat color of variousprepackaging treatments of groups of pork chops having a pH of about5.5, and other groups of chops having a pH of about 5.8. In all thesetests, the chops were packaged in an atmosphere containing 50 percentCO₂, 11 percent O₂ and the balance consisting essentially of N₂. Thecontrol chops were not treated prior to packing, but in the case of theother chops, various types of aqueous solutions were used to pretreatthe chops before packing in the modified gaseous atmosphere. Thetreatments employed are shown in the footnotes to Table X where theresults of these tests are tabulated.

Both the treated and control chops were stored at 34° F. in packagescontaining the described modified atmosphere. After storage of the chopsfor the number of days specified in the first column of Table X, thepackages were then opened and the chops displayed in a meat case at 38°F. for the number of display days shown in the Table. While sodisplayed, the chops were periodically observed to determine the numberwhich had become unacceptably discolored. The number of suchunacceptably discolored chops is shown in Table X under the columnswhich are headed "Days in Display at 38° F.".

From the results entered in Table X, it will be perceived thatTreatments 2 and 3, utilizing the buffer solution of the presentinvention, whether the solution is applied to the pork chops by pumpingor by spraying, reduces the number of chops becoming unacceptablydiscolored after the period in storage at 34° F., followed by display at38° F. The results obtained were especially good when the chops werepumped (injected) with the buffer solution. The tabulated data alsoshows that the use of the three component buffer solution forpretreating the chops yielded substantially better results, in terms ofunacceptable discoloration, than did pumping the chops with an aqueousphosphate solution containing only the phosphate. Finally, the data inTable X shows that, although all chops not pretreated and stored in themodified atmosphere developed some unacceptable discoloration, theextent of such discoloration is much greater in the case of the low pHchops than in the case of chops having a pH of around 5.8.

                                      TABLE X                                     __________________________________________________________________________    Number of Unacceptably Discolored Chops                                       Days in    Low pH Loin (pH about 5.5)                                                                      High pH Loin (pH about 5.8)                      Modified         Days in Dis-      Days in Dis-                               Atmosphere                                                                           Treat-                                                                            Total No.                                                                           play at 38° F.                                                                     Total No.                                                                           play at 38° F.                      (34° F.)                                                                      ment*                                                                             of Chops                                                                            0  1  2  3  of Chops                                                                            0 1 2 3                                    __________________________________________________________________________     5     1   24    0  -- 0  2  24    0 --                                                                              0 0                                           2   24    0  -- 0  0  24    0 --                                                                              0 0                                           3   24    1  -- 1  1  24    0 --                                                                              0 0                                           4   24    3  -- 4  4  24    0 --                                                                              0 0                                    12     1   24    6  6  8  8  23    0 0 1 1                                           2   24    0  0  0  0  24    0 0 0 0                                           3   24    2  3  6  6  24    0 0 0 0                                           4   23    13 13 17 17 22    4 4 6 6                                    19     1   23    7  7  7  8  23    0 0 0 0                                           2   23    0  0  0  0  24    0 0 0 0                                           3   24    4  4  4  4  24    0 0 0 0                                           4   24    7  8  9  10 24    5 5 8 10                                   26     1   23    9  8  9  10 23    4 3 4 4                                           2   24    0  0  0  0  24    0 0 0 0                                           3   23    4  4  5  6  24    0 0 0 0                                           4   23    13 12 14 15 24    7 5 7 7                                    __________________________________________________________________________     *The treatments used were:                                                    1. Aqueous solution containing 3.3 weight percent sodium tripolyphosphate     was pumped (injected) into the chops in an amount equal to 10 weight          percent, based on the weight of the meat.                                     2. An aqueous buffer solution containing 3.3 weight percent sodium            pyrophosphate, 0.45 weight percent ascorbic acid and 0.25 weight percent      citric acid pumped into the chops in an amount equal to 10 weight percent     based on the weight of the meat.                                              3. Same buffer solution as treatment 2, except sprayed on in an amount        equal to 3 weight percent, based on the weight of the meat.                   4. Control  no pretreatment before packing in modified atmosphere.       

EXAMPLE 3

Meat surface color tests were carried out on a group of untreated porkchops having a pH of about 5.5, and on a second group of chops having apH of about 5.8, after both types of chops had been packed in a modifiedatmosphere containing 60 percent CO₂, 10 percent O₂ and 30 percent N₂.These chops were periodically tested to determine the effective colorshelf life of the chops, and these results are graphically portrayed inFIG. 2 of the drawings. The surface color values which are here used onthe ordinate of the graph range from 1 to 7, and the meanings of theassigned values are those which are explained in connection with TableIV above. A color value lower than 4 is generally unacceptable.

As shown in FIG. 2, untreated cuts of relatively lower pH (about 5.5)have a marginally acceptable initial surface color, and the surfacecolor deteriorates relatively rapidly, so that very shortly after 14days in storage, the color of the chops is clearly unacceptable. Thechops having a relatively higher pH of about 5.8 have relatively goodcolor stability when packed in the relatively high CO₂ atmosphere, andthis is true although these chops have not been pretreated with anysolution to purposely undertake to stabilize or elevate the surfacecolor of the meat. As shown in FIG. 2, the high pH chops had arelatively stable surface color value of 6 for a storage period of 28days.

EXAMPLE 4

FIGS. 3 and 4 are graphs which undertake to compare variouscharacteristics or properties of untreated pork chops having a pH ofabout 5.8, and stored in a modified atmosphere over an extended period,with the properties of chops of about the same pH which have beenpretreated with the buffer solution of the present invention, and thensimilarly stored. The aqueous buffer solution pretreatment was effectiveto incorporate into the treated meat, about 0.33 weight percent ofsodium pyrophosphate, about 0.045 weight percent of ascorbic acid andabout 0.025 weight percent of citric acid. Both the untreated controlchops and the treated chops were packed in the modified atmospheredescribed in Example 3.

In referring to FIGS. 3 and 4, the legend identifies the several meatcharacteristics and properties graphed. A microbial total plate countincubated at 10° C. was obtained, and was measured in log₁₀ count persquare inch of meat surface. The odor is here measured on a scale offrom 1 to 4 with the relatively lower values indicating a relativelymore offensive odor, and the relatively higher values indicating moreacceptable meat in terms of the absence of off-odor. The meat surfacecolor scale of from 1 to 7 is that which has already been explained inExample 3, and in referring to Table IV. The overall quality (tastepanel scores) is also measured on a 1 to 7 scale, with the higherquality being indicated by a higher value.

As FIGS. 3 and 4 are compared, it will be noted that treatment with thebuffer solution of the present invention, followed by storage of thechops in a modified atmosphere, substantially improves the odorcharacteristic of the chops and aids the modified atmosphere insuppressing mibrobial activity beyond the 14th day of storage. Theoverall quality of the chops, including taste treats by a taste panel,is substantially higher in the case of the buffer solution treated chopsthan in the case of the untreated chops.

EXAMPLE 5

In similar fashion to the tests carried out on chops having a pH ofabout 5.8 to develop the data graphed in FIGS. 3 and 4, similar tests ontreated and untreated chops having a pH of about 5.5 were carried out todevelop the data graphed in FIGS. 5 and 6. In FIG. 5, chops having a pHof about 5.5, but not pretreated (and thus constituting the controlchops), were placed in a modified atmosphere of the type described inExample 3. Other chops having a relatively low pH of about 5.5 weretreated using the buffer solution of the present invention having thecomposition referred to above in explaining the treatment of the chopstested, and the results tabulated in FIG. 6. In FIGS. 5 and 6 portrayingthe results of testing the treated chops of pH 5.5, the same propertiesand characteristics were tested, and the plotted data lines areillustrated using the same data point symbols, as are described in thelegend appearing in FIG. 3 of the drawings.

When FIGS. 5 and 6 are compared, it will be noted that the color of theuntreated control chops rapidly deteriorates and becomes unacceptableafter about 8 days. The color is stabilized, however, in the case of thelower pH chops treated with the buffer solution of the invention, andthen packed in the modified atmosphere. Here the color remains ofacceptable value for a period in excess of 21 days. It will also benoted that in the case of both the untreated and buffer solution treatedchops, the relatively high carbon dioxide modified atmosphereeffectively inhibits microbial growth to unacceptable levels untilpost-28 day storage.

Comparison of FIGS. 5 and 6 also shows that the odor characteristic ofthe treated chops is improved over that which characterizes the chopswhich were untreated. The overall quality (taste panel scores) of thetreated chops was also better than those which had not received anypretreatment.

EXAMPLE 6

The effect of the storage of pork chops in a modified atmosphere,vis-a-vis, is graphically portrayed in FIG. 7 of the drawings. Here,untreated chops having a pH of about 5.5 are divided into two groups.One of the groups of chops is packaged in air; the other is packaged ina modified atmosphere of the composition described in Example 3. Over a28-day storage period, the bacterial count development in air has beenmeasured at 7-day intervals, as has the odor. FIG. 7 shows that the pH5.5 chops which are packed in the modified atmosphere exhibit asubstantially suppressed microbial growth, and thus have a quiteacceptable bacterial level after 28 days of storage. The chops packagedin the modified atmosphere also exhibit a markedly better odorcharacteristic at the 28-day test and subsequently thereto, as comparedto chops packed in air.

FIG. 8 is a graphic portrayal of the results obtained when pork chopshaving a pH of about 5.8 are packaged in air and in relatively high CO₂modified atmosphere. Again, it will be noted that the use of themodified atmosphere substantially inhibits bacterial growth and preventsthe development of significant off-odor.

EXAMPLE 7

Table XI and FIGS. 9-15 of the drawings enable a comparison to be madeof the shelf life days of acceptable meat color and overall appearanceof pork chops which have had no pretreatment and chops which have beenvariously pretreated. The treated chops used in these tests were allfrom the same loin, and after pretreatment each had a pH in the range offrom about 5.5 to about 5.8. All of the chops were packaged in anatmosphere which contained about 60 percent CO₂, about 10 percent O₂ andabout 30 percent N₂.

                                      TABLE XI                                    __________________________________________________________________________    Component               Shelf-Life                                            Present and Composition (Day)*               Ascorbic                         Treat       Ascorbic                                                                            Citric    Overall                                                                            pH          Acid Level                       ment                                                                              Phosphates                                                                            Acid  Acid  Meat                                                                              Appear-                                                                            of  Percent                                                                            TBA                                                                              (ppm) Off-Odor                   Code                                                                              (0.33%) (450 ppm)                                                                           (100 ppm)                                                                           Color                                                                             ance Chop                                                                              Purge                                                                              Lean                                                                             (day) Meat                                                                             Bone                    __________________________________________________________________________    1   No Treatment         7   7   5.58                                                                              5.85 .20      4.0                                                                              2.7                     2   X       X     X     28  28   5.74                                                                              2.75 .72                                                                              210(14)                                                                             4.0                                                                              4.0                                                                  130(21)                                                                        90(28)                          3   X       X           21  21   5.72                                                                              1.91 .25                                                                              150(14)                                                                             4.0                                                                              4.0                                                                   90(21)                                                                        60(28)                          4   X             X     21  21   5.66                                                                              1.87 .33      4.0                                                                              3.3                     5           X     X     21  21   5.57                                                                              8.07 .23                                                                              160(14)                                                                             3.7                                                                              3.7                                                                  110(21)                                                                        80(28)                          6   X                   28  21   5.79                                                                              2.19 .38      4.0                                                                              3.0                     7           X           21  21   5.62                                                                              7.54 .38                                                                              140(14)                                                                             4.0                                                                              3.7                                                                   90(21)                                                                        60(28)                          8                 X     14  14   5.51                                                                              8.84 .54      4.0                                                                              3.3                     __________________________________________________________________________     *Shows the day after packing when color and overall appearance became         unacceptable.                                                            

The results tabulated in Table XII and graphed in FIGS. 16-23 show theresults of various treatments of pork chops derived from the same loin.After pretreatment with various aqueous solutions, the chops had the pHvalues shown in the table in the range of from about 6.2 to about 6.5.These chops were packaged in the same modified gaseous atmosphere asthat used in the tests yielding the results tabulated in Table XI.

                                      TABLE XII                                   __________________________________________________________________________    Component             She1f-Life                                              Present and Composition                                                                             (Day)*               Ascorbic                           Treat     Ascorbic                                                                            Citric    Overall                                                                            pH          Acid Level                         ment                                                                              Phosphates                                                                          Acid  Acid  Meat                                                                              Appear-                                                                            of  Percent TBA                                                                           (ppm)  Off-Odor                    Code                                                                              (0.33%)                                                                             (450 ppm)                                                                           (100 ppm)                                                                           Color                                                                             ance Chop                                                                              Purge                                                                              Lean                                                                             (day)  Meat                                                                             Bone                     __________________________________________________________________________     9  No Treatment      28  28   6.23                                                                              4.66 .73       4.0                                                                              4.0                      10  X     X     X     28  28   6.32                                                                              1.00 .48                                                                              140(14)                                                                              4.0                                                                              4.0                                                                 70(21)                                                                        40(28) -11                                                                           X  X  28 28 6.37 0.69 .7                                                         0 110(14)  3.7 3.3                                                  70(21)                                                                        50(28)                             12  X           X     28  28   6.32                                                                              0.87 .87       4.0                                                                              3.7                      13        X     X     28  21   6.31                                                                              4.63 .72                                                                              80(14) 4.0                                                                              3.7                                                                 50(21)                                                                        40(28)                             14  X                 28  28   6.42                                                                              0.84 .69       4.0                                                                              3.3                      15        X           21  21   6.31                                                                              5.46 .92                                                                              80(14) 4.0                                                                              3.7                                                                 60(21)                                                                        40(28)                             16              X     21  21   6.40                                                                              5.09 .94       4.0                                                                              3.7                      __________________________________________________________________________     *Shows the day after packing when color and overall appearance became         unacceptable.                                                            

It will be noted from a comparison of Tables XI and XII and the graphsbased thereon, that the chops derived from the relatively high pH loinsexhibit an acceptable color shelf life of about 28 days without benefitof any pretreatment. The relatively low pH chops, however, when nottreated prior to packing in the modified atmosphere, exhibit a colorshelf life of only about 7 days. The data appearing in Tables XI and XIIfurther show that the buffer solution containing all three of the activecomponents hereinbefore described functions more effectively inextending the meat color shelf life and the overall appearance shelflife than does a solution which contains only one or even two of thesecomponents. This is most apparent in the case of the relatively low pHchops, but it is also easily discernible from a close comparison of theoverall values obtained in the testing of the relatively higher pHchops.

It will be noted in referring to Tables XI and XII that thedecomposition rate of the ascorbic acid component is tabulated. Thisvalue is of interest in that it is desirable for as little of theascorbic acid as possible to remain at the time of consumer acquisitionafter about 21 days.

EXAMPLE 8

Two fresh prime ribs of beef were cut into steaks used in a test fordetermining the response of beef to processing in accordance with thepresent invention. From one of the prime ribs, ten boneless ribeyesteaks each having a thickness of about one inch were cut and wereutilized in tests as control (untreated) steaks and, in alternatesequence, as treated steaks, as will be further explained in referringin detail to the tests. From the second of the fresh prime ribs,fourteen boneless ribeye steaks of one inch thickness were cut, and werealso utilized in alternate treatment series as control steaks andtreated steaks.

Steaks denominated as control steaks were included in a treatment seriesassigned an odd number (1, 3 and 5) and were not pre-treated with thethree component treating composition of the present invention ashereinbefore described, but were directly packaged in a modifiedatmosphere. The steaks included in the treatment series denominated byan even number (2, 4 and 6) were treated with an aqueous treatingsolution containing 0.28 weight percent of polyphosphate compound, 0.025weight percent (250 ppm) of citric acid and 0.045 weight percent ofascorbic acid, all referring to the weights of the particular chemicalcomponent in relation to the total weight of the treated steak followingtreatment. The treating composition was applied as an aqueous spray tothe external surfaces of the steaks, and the water content of theapplied treating solution constituted 2.15 weight percent of the totalweight of the treated steaks.

In all of these treatment series (1-6), each steak, whether a treated orcontrol sample, was packaged in a modified atmosphere. The package wasthen opened after a certain period of time of storage at 32±2° F.,referred to as the storage interval, and tests were then made of thesteak in the package at the time of opening. The color of the meat wasobserved, and tests were also made of the microbial population, and ofthe odor and taste properties of the particular meat sample in thepackage opened after the respective storage interval.

The storage time intervals at 32° F. used in the case of all of thesamples of both treated and control steaks from both of the prime ribsand for the purpose of determining the composition of the modifiedatmosphere in the package, were 4 days, 11 days, 18 days and 25 days.The compositions of the modified gaseous atmospheres determined to existin each of the several packages after the identified storage intervalsare set forth in Table XIII.

The eight steaks making up Treatment Series No. 3 and Treatment SeriesNo. 4 were cut from the same prime rib (referred to as Rib No. 1). Thetwo steaks placed in the packages opened after the twenty-fifth day ofstorage in Treatment Series No. 1 and in Treatment Series No. 2 werealso cut from Prime Rib No. 1. Thus, a total of ten steaks cut fromPrime Rib No. 1 were used in these ten packages making up TreatmentSeries No. 3 and Treatment Series No. 4 in their entirety, and the two25 day storage interval steak samples in the case of Treatment SeriesNo. 1 and 2.

                  TABLE XIII                                                      ______________________________________                                        Modified Atmosphere Composition, Percent                                      MA.sup.+                                                                      Storage                                                                       Intervals        Treatment Series                                             at 32° F.(Day)                                                                   Gas    1      2    3     4    5     6                               ______________________________________                                                                     *     *                                           4        CO.sub.2                                                                             53.9   46.5 50.2  50.6 50.1  36.9                                      O.sub.2                                                                              20.9   20.7 20.6  21.1 21.5  20.8                                      N.sub.2                                                                              25.2   32.9 29.2  28.2 28.4  42.3                                                         *     *                                          11        CO.sub.2                                                                             48.6   48.2 53.3  47.4 52.3  52.4                                      O.sub.2                                                                              19.8   19.4 20.5  20.4 20.5  20.6                                      N.sub.2                                                                              31.6   32.3 26.2  32.2 27.2  27.0                                                         *     *                                          18        CO.sub.2                                                                             50.3   25.8 27.7  46.2 54.4  41.9                                      O.sub.2                                                                              19.4   18.5 18.2  19.2 20.1  18.7                                      N.sub.2                                                                              30.3   55.6 54.0  34.6 25.5  39.4                                             *      *    *     *                                          25        CO.sub.2                                                                             48.1   54.8 54.4  53.0 24.4  43.1                                      O.sub.2                                                                              18.0   18.6 19.2  19.5 18.4  18.4                                      N.sub.2                                                                              33.9   26.6 28.5  27.5 57.2  38.5                            ______________________________________                                         * These steaks were cut from Prime Rib No. 1.                                 The remaining steaks were cut from Prime Rib No. 2.                           .sup.+ MA = modified atmosphere                                          

In addition to determining the composition of the modified gaseousatmosphere in each package after the identified storage intervals, thesurface color of each steak was observed.

In these tests, the packaged steaks were stored at 32±2° F., after whichthe packages were placed in a typical meat case display environment inwhich the temperature was 36±2° F. A small hole was made through thepackage at this time to allow the ambient atmosphere to slowly enter thepackage, and in this respect, to simulate the typical equilibration ofgaseous environment of the sort occurring upon actual display of themeat in the retail meat case. After this, on each of the succeedingthree days, the coloration of the meat was observed, and the colorvalues of the observed meat are set forth in Table XIV.

                  TABLE XIV                                                       ______________________________________                                        Meat Surface Color                                                            MA Storage                                                                              Days In                                                             Intervals,                                                                             Display Case                                                                             Treatment Series                                          32° F. (Day)                                                                    at 36° F.                                                                         1      2    3    4    5    6                              ______________________________________                                         4       0          6.5    6.5  6.5  6.5  6.5  7.0                                     1          6.0    6.5  6.0  6.5  6.0  6.5                                     3          3.5    5.5  4.5  6.0  4.0  6.0                            11       0          5.0    6.5  5.0  6.5  5.0  6.5                                     1          4.0    5.5  5.0  6.5  5.0  6.5                                     2          3.5    5.5  4.5  6.0  4.5  6.0                                     3          3.0    5.5  4.5  6.0  4.5  6.0                            18       0          3.5    6.0  4.5  6.0  4.5  6.0                                     1          3.5    6.0  4.5  6.0  4.5  6.0                                     2          3.0    5.5  4.5  6.0  4.5  6.0                                     3          3.0    5.0  4.0  6.0  4.0  6.0                            25       0          3.0    6.0  4.0  6.0  5.0  6.0                                     1          2.0    5.0  4.0  6.0  2.0  6.0                                     2          1.5    5.0  4.0  5.5  2.0  6.0                                     3          1.0    5.0  4.0  5.5  2.0  6.0                            ______________________________________                                    

It will be perceived, by reference to Table XIV, that in the case of thesteaks in Treatment Series Nos. 2, 4 and 6, the color of the beef didnot drop below 5.0 so as to become unacceptable, even after 25 days inmodified atmosphere storage and 3 days in display. On the other hand,the samples of beef steak which were not treated with the aqueousthree-component composition in accordance with the present inventiongenerally became of unacceptable color following about 11 days ofstorage. The present invention treatment is thus clearly effective, whencoupled with storage in the modified atmosphere prescribed by theinvention, to prevent the loss of the fresh color of the beef steaksover extended storage and display intervals.

The pH, percentage of purge (in weight percent of the total weight ofthe steak) and off-odor were also measured and observed following thestorage and display periods to which the several steaks were subjected.Thus, these measurements and observations were made following theinitial storage period at 32° F., and the then ensuing three day displayperiod at 36° F. The results of these measurements of pH, weight percentpurge, and off-odor for Treatment Series 1-6 are set forth in Tables XV,XVI and XVII. In evaluating the off-odor characteristic of the beefsteaks, an off-odor value of less than 3 was considered to be generallyunacceptable and indicative of the progression of rancidity to anunacceptable level.

                  TABLE XV                                                        ______________________________________                                        pH Values of Tested Steaks                                                    MA Storage Plus                                                               Display Intervals                                                                         Treatment Series                                                  (Total Days)                                                                              1      2       3    4     5    6                                  ______________________________________                                         1          5.54   5.63    5.49 5.64  5.50 5.62                                7          5.70   5.63    5.54 5.63  5.52 5.64                               14          5.63   5.63    5.55 5.64  5.66 5.63                               21          5.63   5.70    5.62 5.78  5.63 5.69                               28          5.64   5.79    5.70 5.74  5.66 5.77                               ______________________________________                                    

                  TABLE XVI                                                       ______________________________________                                        Percent of Purge From Steaks                                                  MA Storage Plus                                                               Display Intervals                                                                         Treatment Series                                                  (Total Days)                                                                              1      2       3    4     5    6                                  ______________________________________                                         l          1.09   2.84    1.34 1.54  1.64 1.99                                7          3.33   2.99    3.55 2.67  3.61 2.87                               14          3.36   3.31    4.40 3.11  4.65 3.24                               21          4.10   4.20    3.94 3.74  4.77 3.64                               28          4.40   4.19    5.15 3.93  4.18 3.16                               ______________________________________                                    

                  TABLE XVII                                                      ______________________________________                                        Off-Odor                                                                      MA Storage Plus                                                               Display Intervals                                                                         Treatment Series                                                  (Total Days)                                                                              1      2       3    4     5    6                                  ______________________________________                                         1          4      4       4    4     4    4                                   7          4      4       4    4     4    4                                  14          3      4       4    4     4    4                                  21          2      4       3    4     3    4                                  28          1      3       3    2     2    3                                  ______________________________________                                    

In addition to the evaluation of parameters hereinbefore described, thesteaks in Treatment Series No. 1 (control) and Treatment Series No. 2(treated) were subjected to TBA analysis after the total storage anddisplay intervals utilized, and in each case, the lean meat portion, aswell as the fat portion, of each of the beef steaks was tested for TBAvalue. A TBA value exceeding about 1.50 was considered to indicate anunacceptable steak. The results of these tests appear in Table XVIII.

                  TABLE XVIII                                                     ______________________________________                                        TBA Analysis                                                                  MA Storage Plus                                                               Display Intervals                                                                          Type        Treatment Series                                     (Total Days) of Meat     1        2                                           ______________________________________                                         1           Lean        0.30     0.08                                                     Fat         0.19     0.06                                         7           Lean        1.40     0.14                                                     Fat         0.53     0.08                                        14           Lean        2.70     0.55                                                     Fat         1.00     0.17                                        21           Lean        3.00     0.66                                                     Fat         1.20     0.20                                        28           Lean        4.00     0.66                                                     Fat         2.20     0.36                                        ______________________________________                                    

From these results, it can be seen that the lean meat in the control(untreated) steaks of Treatment Series No. 1 developed an unacceptableTBA level after the fourteenth day, whereas the Treatment Series No. 2treated steaks (both the fat and the lean portions) remained acceptablylow in TBA value through the twenty-eighth day.

A six-member taste panel carried out flavor, texture and juicinesstests, and rendered overall sensory impressions of the control andtreated samples of the beef steaks from Prime Ribs No. 1 and No. 2 afterthey had been stored for the hereinbefore described intervals, and thendisplayed for an additional three days. The taste panel was able tocompare the changes in flavor, texture and juiciness of untreated andtreated beef steak samples occurring over various extended periods ofstorage. In performing this testing, each of the untreated steaks in theNo. 1, 3 and 5 control treatment series was cooked and then cut into twoparts, making a portion for each member of the taste panel. The same wasdone with each of the treated steaks from the No. 2, 4 and 6 treatmentseries. The cooked test samples were distributed so that each panelmember was comparing treated and untreated steaks from the same primerib.

The averaged results of the panel's testing with indicated standarddeviations are set forth in Table XIX, and the footnotes to that tablegive the criteria employed in the tests for the degree of excellence, orlack of it, assigned to each tested steak.

                                      TABLE XIX                                   __________________________________________________________________________    Taste Panel Tests*                                                            Storage                                                                              Cook                                                                   Intervals                                                                            Yield,                                                                             Total             Off Flavor**                                                                         Overall                                  (Total Days)                                                                         Percent                                                                            Flavor                                                                              Texture                                                                             Juiciness                                                                           Lean   Impression                               __________________________________________________________________________     1                                                                            Control                                                                              81.4 4.92 ± 0.66                                                                      4.67 ± 0.52                                                                      5.00 ± 0.63                                                                      1.25 ± 0.42                                                                       4.92 ± 0.20                           Treated                                                                              87.1 5.33 ± 0.52                                                                      4.67 ± 0.82                                                                      5.17 ± 0.75                                                                      1.08 ± 0.20                                                                       5.25 ± 0.20                           Contro1                                                                              72.5 3.58 ± 0.80                                                                      4.25 ± 0.61                                                                      3.92 ± 0.92                                                                      1.83 ± 0.98                                                                       3.42 ± 1.02                           Treated                                                                              79.1 4.42 ± 0.66                                                                      4.08 ± 0.66                                                                      4.25 ± 0.89                                                                      1.50 ± 0.52                                                                       4.08 ± 0.80                           14                                                                            Control                                                                              77.1 4.58 ± 0.49                                                                      4.25 ± 0.42                                                                      4.08 ± 0.20                                                                      1.33 ± 0.52                                                                       4.25 ± 0.42                           Treated                                                                              80.6 5.17 ± 0.41                                                                      4.67 ± 0.82                                                                      4.67 ± 0.52                                                                      1.17 ± 0.41                                                                       5.17 ± 0.41                           21                                                                            Control                                                                              82.6 3.58 ± 0.49                                                                      4.17 ± 0.98                                                                      4.33 ± 1.37                                                                      1.67 ± 0.52                                                                       3.42 ± 0.80                           Treated                                                                              81.7 44.17 ± 0.41                                                                     4.50 ± 0.52                                                                      5.00 ± 1.10                                                                      1.50 ± 0.84                                                                       4.08 ± 0.49                           28                                                                            Control                                                                              81.3 3.83 ± 0.75                                                                      4.33 ± 0.82                                                                      4.17 ± 0.41                                                                      2.25 ± 1.08                                                                       4.00 ± 0.63                           Treated                                                                              80.7 4.83 ± 0.41                                                                      4.33 ± 0.52                                                                      4.50 ± 0.52                                                                      1.00 ± 0.00                                                                       4.58 ± 0.49                           __________________________________________________________________________     *Total Flavor/Texture/Juiciness/Overall Impression                            7 = Excellent                                                                 6 = Very good                                                                 5 = Good                                                                      4 = Fair                                                                      3 = Poor                                                                      2 = Very poor                                                                 1 = Extremely poor                                                            **Off Flavor                                                                  5 = Very strong off flavor                                                    4 = Strong off flavor                                                         3 = Moderate off flavor                                                       2 = Weak off flavor                                                           1 = Absent/no off flavor                                                 

The results of the taste panel testing set forth in Table XIX clearlyindicate that steaks treated and then packaged in accordance with thisinvention generally have a better flavor and better juiciness than thecontrol or untreated steaks, while the texture of the two types ofsteaks is not markedly different. The overall results obtained, asreflected in the column identified as "Overall Impression", shows aclear preference of the panel members for the treated steaks. Probablyas a result of the lesser amount of purge which is lost from the treatedsteaks, or at least related to that parameter, is the determination ofresults set forth in Table XIX, and there identified as the percentageyield upon cooking realized from the several samples tested. A higheryield is realized upon cooking the treated steaks than that which isrealized upon cooking of the untreated control steaks up until thetwenty first day of storage and display, at which point the yield is notsignificantly different as between the control and treated steaks.

EXAMPLE 9

The importance of the bacteria log count, as a measure of the microbialcondition of the meat, has been hereinbefore discussed. Generally, intesting the microbial growth in fresh meat samples, a bacteria log countvalue which exceeds 6.5 per square inch of meat surface is considered tobe excessive, and to be indicative of unacceptable meat spoilage. Ofcourse, in Treatment Series No. 1 through No. 6 in the tests underconsideration, the modified atmosphere used in every package contained arelatively high amount of carbon dioxide. The bacteria log count,therefore, did not exceed an unacceptable level, even after thetwenty-eighth day of storage and display. This is shown in Table XX.

                  TABLE XX                                                        ______________________________________                                        Bacteria Log Count/In.sup.2, Meat, l0° C.                              MA Storage                                                                    Plus Display                                                                  Intervals                                                                              Treatment Series                                                     (Total Days)                                                                           1       2       3     4     5     6                                  ______________________________________                                         7       <1.40   <1.40   1.40  <1.40 <1.40 <1.40                              14       1.40    <1.40   <1.40 <1.40 1.70  <1.40                              21       <1.4    1.4     <1.4  <1.4  <1.4  2.0                                28       2.60    2.60    <1.4  1.4   1.88  2.0                                ______________________________________                                    

EXAMPLE 10

From two additional fresh prime ribs (No. 3 and No. 4), a number ofadditional rib eye steaks of approximately one inch thickness were cut.Ten of the rib eye steaks were cut from each of the two prime ribs, andwere used to make up the twenty packages divided into four TreatmentSeries, No. 1-No. 4, for testing purposes as hereinafter described. Theconcentration of gases in the modified atmosphere in each package wasascertained after time intervals of 2, 4, 11, 18 and 25 days at 32° F.Surface color, pH, percent of purge, off-odor and TBA values wereascertained after the initial storage period of 32° F., plus anadditional time interval equivalent to 3 days of display in a meat caseat 36° F. In these tests, the steaks used in Treatment Series No. 1 andTreatment Series No. 2 were untreated control steaks packaged in air andin the modified atmosphere of this invention, respectively. The steaksused in Treatment Series No. 3 and No. 4 were treated with the samethree component treating solution as that described in Example 8 inreferring to the testing of steaks cut from Prime Ribs No. 1 and No. 2.The No. 3 Treatment Series steaks were then packaged in air, and the No.4 Treatment Series steaks were packaged in a modified atmosphereconstituted in accordance with the invention.

The results of the testing of the gaseous atmosphere in the severalpackages after the described time intervals is reported in Table XXI.

                  TABLE XXI                                                       ______________________________________                                        Composition of Gaseous Packaging Atmosphere                                   MA Storage                                                                    Intervals           Treatment Series                                          (Day)      Gas      1      2       3    4                                     ______________________________________                                         2         CO.sub.2 1.5    53.4    1.8  51.0                                             O.sub.2  21.4   23.1    21.3 23.7                                             N.sub.2  77.1   23.5    76.9 25.3                                   4         CO.sub.2 2.4    53.4    2.6  50.2                                             O.sub.2  20.8   22.6    20.7 23.0                                             N.sub.2  76.7   24.0    76.7 26.8                                  11         CO.sub.2 2.1    51.6    2.7  51.4                                             O.sub.2  20.4   22.1    19.8 22.2                                             N.sub.2  77.5   26.2    77.5 26.4                                  18         CO.sub.2 5.3    53.4    5.7  52.6                                             O.sub.2  16.6   21.5    16.0 21.7                                             N.sub.2  78.1   25.1    78.3 25.7                                  25         CO.sub.2 13.6   52.7    16.6 52.0                                             O.sub.2  4.7    21.3    1.5  21.7                                             N.sub.2  81.7   26.0    81.8 26.3                                  ______________________________________                                    

Observations of the surface color of the steaks were made at timeintervals defined by the period of storage at 32° F., and then, aftereach such interval, upon certain following days at which the severalsamples were retained at the typical meat case display temperature of36° F. In the latter case, observations were made on the second andthird days of storage at the meat case temperature. The results of theseobservations are set forth in Table XXII.

                  TABLE XXII                                                      ______________________________________                                        Meat Surface Color                                                            MA Storage                                                                             Days In                                                              Intervals                                                                              Meat Case  Treatment Series                                          (Day)    Display    1      2       3    4                                     ______________________________________                                         4       0          6.0    6.0     6.5  6.5                                            2          5.0    5.5     6.5  6.5                                            3          5.0    5.5     6.5  6.5                                   11       0          6.0    6.0     7.0  7.0                                            2          5.0    4.5     6.5  7.0                                            3          3.0    3.0     6.5  7.0                                   18       0          4.0    4.0     7.0  7.0                                            2          4.0    4.0     7.0  7.0                                            3          2.0    2.0     5.0  7.0                                   25       0          2.0    1.0     6.0  6.0                                            2          2.0    1.0     2.0  6.0                                            3          1.0    1.0     1.0  6.0                                   ______________________________________                                    

As previously indicated, a color evaluation of less than 5.0 indicatesunacceptable discoloration. It will thus be noted that even at the thirdday at meat case display temperatures, following 18 days of modifiedatmosphere storage at 32° F., the treated steaks continued to have anacceptable fresh meat appearance.

The several steaks used in Treatment Series No. 1 through No. 4 weretreated for bacteria log count after the several modified atmospherestorage intervals at 32° F., plus the 3 days retention at the meat casedisplay temperature of 36° F. The results of the bacteria log counttests are set forth in Table XXIII.

                  TABLE XXIII                                                     ______________________________________                                        Bacteria Log Count/In.sup.2, Meat, 10° C.                              MA Storage Plus                                                               Display Intervals                                                                           Treatment Series                                                (Total Days)  1      2          3    4                                        ______________________________________                                         2            3.15   2.26       1.88 1.88                                      7            5.32   2.93       6.40 2.92                                     14            6.97   2.60       6.93 2.54                                     21            7.62   <1.40      7.74 2.52                                     28            8.85   3.40       9.43 6.38                                     ______________________________________                                    

In the cases of the steaks which were packaged in air, the untreatedsteaks from Prime Ribs No. 3 and No. 4 became unacceptably spoiled andexceeded the acceptable bacterial log count after 14 days in storage.The steaks which were packaged in the modified atmosphere containing ahigh carbon dioxide content remained in good condition and exhibited amicrobial shelf-life exceeding 28 days in each instance.

The measured pH of the steaks after the several time intervals ofstorage is shown in Table XXIV.

                  TABLE XXIV                                                      ______________________________________                                        pH of Tested Steaks                                                           MA Storage Plus                                                               Display Intervals                                                                           Treatment Series                                                (Total Days)  1      2          3    4                                        ______________________________________                                         2            5.52   5.55       5.68 5.65                                      7            5.50   5.50       5.62 5.68                                     14            5.68   5.60       5.74 5.74                                     21            5.89   5.73       5.94 5.72                                     28            5.80   5.70       6.04 5.81                                     ______________________________________                                    

The data set forth in Table XXIV confirms that the treatment of beefwith the treating solution used in the process of the present inventionfunctions to elevate the pH to a value generally in excess of about 5.6.

The results of TBA analysis, in the case of the steak samples derivedfrom Prime Ribs No. 3 and No. 4, are set forth in Table XXV.

                  TABLE XXV                                                       ______________________________________                                        TBA Analysis                                                                  MA Storage Plus                                                               Display Intervals                                                                        Type of   Treatment Series                                         (Total Days)                                                                             Meat      1       2     3     4                                    ______________________________________                                         2         Lean      0.77    0.84  0.06  0.06                                            Fat       0.30    0.50  0.05  0.05                                  7         Lean      2.50    2.60  0.18  0.11                                            Fat       0.98    1.00  0.14  0.09                                 14         Lean      2.20    3.00  0.33  0.25                                            Fat       0.87    0.97  0.11  0.16                                 21         Lean      2.60    3.80  0.72  0.66                                            Fat       1.30    1.20  0.50  0.34                                 28         Lean      4.90    6.60  1.20  1.20                                            Fat       2.20    3.00  0.64  0.58                                 ______________________________________                                    

From the tabulated results of TBA testing, it will be perceived that themaximum acceptable TBA value of 1.50 was not exceeded in the case of thesteaks used in Treatment Series No. 3 and No. 4 even after 28 days ofstorge and display. By contrast, the steaks used in Treatment Series No.1 and No. 2 which had not been treated with the aqueous treatingsolution exceeded the maxium accepable TBA value, especially in the caseof lean meat, after only seven days.

Table XXVI summarizes the time intervals (shelf-lives) over which thebeef steak samples exhibited satisfactory microbiological properties,acceptably fresh color, minimal off-odor and acceptably low oxidativerancidity, based on the several treatment series carried out on the beefsteaks derived from Prime Ribs No. 3 and No. 4, and hereinbeforedescribed.

                  TABLE XXVI                                                      ______________________________________                                        Shelf-Life (Total Days)                                                                    Treatment Series                                                              1     2         3      4                                         ______________________________________                                        Microbiological                                                                              7       28        7    28                                      Off-Odor       7       21        7    28                                      Color          13      11        25   28                                      Oxidative Rancidity                                                                          <7      <7        28   28                                      Acceptable Overall                                                                           7         7       7    28                                      Shelf-Life                                                                    ______________________________________                                    

The summarization of the results of the test series carried out on therib eye steaks cut from Prime Ribs No. 3 and 4, as set forth in TableXXVI, shows that the modified atmosphere utilized in the packaging ofthe steaks employed in Treatment Series No. 2 retarded bacteria growthand inhibited off-odor from spoilage. On the other hand, the oxidationof heme pigment, resulting in a loss of fresh coloration, and theoxidation of the lipid components in the steak to yield unacceptableoxidative rancidity (as reflected in the TBA results) show thatpackaging in a modified atmosphere alone, and without pre-treatment, isdeleterious with respect to these parameters.

In sum, the use of a modified atmosphere could not effectively increasethe acceptable overall shelf-life of the steaks beyond about 7 days,even though the microbiological shelf-life was extended from 7 days, inthe case of Treatment Series No. 1 steaks which were packaged in air, to28 days for Treatment Series No. 2 steaks which were packaged in themodified atmosphere.

When Treatment Series No. 1 and No. 3 are compared, in the case of thesteaks derived from Prime Ribs No. 3 and 4, pre-treated steaks packagedin air (Treatment Series No. 3), when compared to untreated steaks(Treatment Series No. 1) reveals that the treatment alone had nosignificant effect on bacterial growth, or upon the development ofoff-odor resulting from spoilage. The microbiological shelf-lives of thesteaks in Treatment Series No. 1 and No. 3 were about the same, i.e. 7days. Treatment of the meat with the three component aqueous solutionwas effective, however, to retard the oxidation of heme pigment in themeat, and to reduce the oxidation of the lipid components. This issubstantiated by the increased color shelf-life of the steak samplesused in Treatment Series No. 3 as compared to those used in TreatmentSeries No. 1, and in the reduced TBA values of Treatment Series No. 3 ascompared to Treatment Series No. 1. As a result, however, of the factthat the treatment with the aqueous solution is not alone sufficient toincrease the microbiological shelf-life, no increase in the overallacceptable shelf-life was observed where the steaks were treated withthe aqueous solution, but were then packaged in air. Finally, and mostimportantly, a comparison of all of the steak samples, represented bythe results set forth in treatment Series Nos. 1, 2, 3 and 4, show thatwhere pre-treatment with the three component aqueous solution is coupledwith packaging in a modified atmosphere, the result is that the overallacceptable shelf-life is extended from 7 days to 28 days.

EXAMPLE 11

Four loins of lamb were each cut into eight lamb chops which were eachthree-quarters inch thick. The lamb chops were grouped for testing inthe manner shown in Table XXVII, where L-1, L-2, L-3 and L-4 refer tochops derived from loin 1, loin 2, loin 3 and loin 4, respectively.

                  TABLE XXVII                                                     ______________________________________                                        Loin Derivation of Lamb Chops                                                 MA Storage                                                                    Intervals    Treatment Series                                                 (Days)       1      2          3    4                                         ______________________________________                                         1 + 3*      L-1    L-1        L-1  L-1                                        4 + 3       L-3    L-3        L-3  L-3                                        8 + 3       L-2    L-2        L-2  L-2                                       11 + 3       L-4    L-4        L-4  L-4                                       15 + 3       L-1    L-1        L-1  L-1                                       17 + 3       L-3    L-3        L-3  L-3                                       22 + 3       L-2    L-2        L-2  L-2                                       24 + 3       L-4    L-4        L-4  L-4                                       ______________________________________                                         *Number of days stored at 32° F., followed by three additional day     of display at meat case temperature of 36° F.                     

After storage of the chops in either air or the modified atmosphere, andeither in a treated or untreated condition for varying time intervals,the bacteria log counts of the several lamb chops were measured and theresults tabulated in Table XXVIII. In Treatment Series No. 1 and No. 2the lamb chops were not treated; in Treatment Series No. 3 and No. 4 thechops were treated. The chops in Treatment Series No. 2 and No. 4 werepackaged in a modified atmosphere consituted in accordance with theinvention, and Treatment Series No. 1 and No. 3 were packaged in air.The treating solution used had the same composition as the treatingsolution described in Example 8 in referring to the testing of steakscut from Prime Ribs No. 1 and No. 2. The modified atmosphere usedcontained 60 percent carbon dioxide, 10 percent oxygen and 30 percentnitrogen as constituted at the outset of each treatment series (dayone).

                  TABLE XXVIII                                                    ______________________________________                                         Bacteria Log Count/In.sup.2, 10° C.                                   MA Storage                                                                    Intervals Meat or  Treatment Series                                           (Days)    Bone     1        2     3      4                                    ______________________________________                                         1 + 3*   Meat     3.00     <2.70 3.00   <2.70                                          Bone     3.60     <1.70 3.30   2.30                                  4 + 3*   Meat     4.23     2.99  4.48   2.58                                           Bone     7.38     4.78  6.41   5.05                                  8 + 3*   Meat     5.08     2.95  4.11   2.85                                           Bone     8.42     5.72  7.55   3.94                                 11 + 3*   Meat     6.54     3.18  5.26   3.20                                           Bone     7.53     6.55  8.05   4.90                                 15 + 3*   Meat     8.48     6.51  7.89   5.32                                           Bone     10.03    7.26  8.89   4.67                                 17 + 3*   Meat     7.52     4.43  7.20   3.62                                           Bone     9.40     5.75  9.09   6.24                                 22 + 3*   Meat     8.68     <4.40 6.65   5.95                                           Bone     9.41     6.52  9.81   6.54                                 24 + 3*   Meat     8.65     6.04  7.34   4.70                                           Bone     9.92     6.21  8.92   6.13                                 ______________________________________                                         *Number of days stored at 32° F., followed by three Additional day     of display at meat case temperature at 36° F.                     

The lamb chops used in the test lots represented by Treatment Series No.2 and Treatment Series No. 4 (packaged in a modified atmosphere)consistently exhibited lower bacteria log counts at every testing timeinterval than did the chops which had been stored in air, as representedby Treatment Series No. 1 and No. 3. The microbial growth in the No. 1Treatment Series chops became unacceptably high in both the meat andbone after storage and display interval of fourteen days total time, andafter eighteen total days in the case of the No. 3 Treatment Series lambchops.

The lamb chops in each of Treatment Series Nos. 1-4 were tested forfresh color shelf-life, utilizing the color value of 5.0 as that valuebelow which the color of the chop would be considered to have becomeunacceptable. As in the case of the beef samples previously described,the tests were carried out at the end of various storage intervalsduring which the chops were stored at 32° F., and also during the threedays following the storage interval when the packages were slightlypunctured to allow equilibration with the ambient atmosphere. Duringthis three days "display" period, the chops were retained at a typicalmeat display case temperature of 36° F. The results of these tests areset forth in Table XXIX.

                  TABLE XXIX                                                      ______________________________________                                        Meat Surface Color                                                            MA Storage                                                                    Intervals  Days In                                                            at 32° F.                                                                         Case at     Treatment Series                                       (Day)      36° F.                                                                             1     2      3   4                                     ______________________________________                                         4         0           7.0   7.0    7.0 7.0                                              1           6.0   6.0    7.0 7.0                                              2           6.0   6.0    7.0 7.0                                              3           6.0   6.0    7.0 7.0                                    8         0           5.0   4.5    7.0 7.0                                              1           4.0   4.0    7.0 7.0                                              2           3.0   2.0    6.0 6.0                                              3           3.0   2.0    6.0 6.0                                   11         0           5.0   5.0    6.0 7.0                                              1           5.0   5.0    6.0 7.0                                              2           5.0   5.0    6.0 7.0                                              3           5.0   5.0    5.0 6.0                                   15         0           3.0   1.0    7.0 6.0                                              1           2.0   1.0    6.0 6.0                                              2           1.0   1.0    6.0 6.0                                              3           1.0   1.0    6.0 6.0                                   17         0           6.0   4.5    6.0 6.0                                              1           6.0   4.5    6.0 6.0                                              2           6.0   4.0    5.0 6.0                                              3           6.0   4.0    5.0 6.0                                   22         0           1.0   1.0    5.0 5.0                                              1           1.0   1.0    5.0 5.0                                              2           1.0   1.0    4.5 4.0                                              3           1.0   1.0    4.0 4.0                                   24         0           4.5   4.0    4.0 5.0                                              1           4.5   4.0    4.0 5.0                                              2           4.5   4.0    4.0 4.5                                              3           4.0   3.0    3.0 4.5                                   ______________________________________                                    

It is apparent by reference to Table XXIX that the lamb chops inTreatment Series No. 3 and No. 4 which were treated with the threecomponent treating solution of the present invention, and then storedeither in air or in the modified atmosphere, exhibited better freshcolopr retention than the chops which had not received such treatment(Treatment Series No. 1 and No. 2).

Table XXX shows the TBA values for the lamb chops included in theTreatment Series Nos. 1-4.

                  TABLE XXX                                                       ______________________________________                                        TBA Values                                                                    MA Storage                                                                    Intervals                                                                     at 32° F.                                                                        Type of  Treatment Series                                           (Total Days)*                                                                           Meat     1         2     3      4                                   ______________________________________                                         4        Lean     2.90      1.70  0.59   0.34                                          Fat      0.59      0.83  0.11   0.09                                 7        Lean     0.36      0.72  0.14   0.11                                          Fat      0.17      0.34  0.11   0.08                                11        Lean     0.56      0.92  0.33   0.25                                          Fat      0.34      0.64  0.30   0.19                                14        Lean     0.90      1.90  0.37   0.30                                          Fat      0.55      0.85  0.28   0.46                                18        Lean     7.50      7.30  4.50   4.20                                          Fat      >8.00     >8.00 5.30   5.60                                25        Lean     7.30      7.40  4.10   3.70                                          Fat      1.90      1.60  0.30   0.29                                27        Lean     1.50      2.20  0.30   0.28                                          Fat      0.72      1.70  0.25   0.21                                ______________________________________                                         *Total number of days includes storage in the package at 32° F.,       followed by display for three days display at 36° F.              

Table XXX clearly shows that when the TBA values for chops utilized inTreatment Series No. 1 and No. 2 are compared with the TBA values of thetreated chops used in Treatment Series No. 3 and No. 4, treatment withthe aqueous treating solution used in the initial step of the presentinvention functions generally to retain the TBA values relatively low ascompared to this parameter as measured in the case of the TreatmentSeries No. 1 and No. 2 untreated chops.

EXAMPLE 12

Four additional lamb loins, L-5, L-6, L-7 and L-8, were each cut intoeight lamb chops to be used in another group of treatment series. Theloins from which the several tested chops were derived are shown inTable XXXI. In this second group of treatment series, numbered 1 through6, the lamb chops were tested after varying time intervals. These timeintervals each encompassed a cold storage packaged initial interval at32° F., followed by a three day meat case display interval at 36° F. InTable XXXII, the observed surface color of the meat, as noted duringthese time intervals for the lamb chops in all six treatment series, isset forth. In these series of tests, Treatment Series Nos. 2, 4 and 6were tests of chops treated with the treating solution of the presentinvention before packaging. Treatment Series Nos. 1, 3 and 5 used chopswhich were not treated. The treating solution used contained the samecomponents in the same concentration as referred to in Example 8.

It will be noted that in the treated chops utilized in the TreatmentSeries No. 2, No. 4 and No. 6, the meat surface color ratings remainedhigh through the twenty-third day of storage and through the third dayof display thereafter. The untreated chops, on the other hand, becameunacceptably discolored as early as the fifth day of storage, and thethird day thereafter at the meat case display temperature. Thus, thetests confirmed that treatment in accordance with the present inventionsubstantially enhanced the retention of the fresh meat color in the lambchops.

                  TABLE XXXI                                                      ______________________________________                                        Loin Derivation of Lamb Chops                                                 MA Storage                                                                    Intervals                                                                              Treatment Series                                                     (Days)   1        2      3      4    5      6                                 ______________________________________                                         2 + 3   L-5      L-5    L-6    L-6  L-7    L-7                                5 + 3   L-8      L-8    L-5    L-5  L-6    L-6                               11 + 3   L-7      L-7    L-8    L-8  L-5    L-5                               16 + 3   L-6      L-6    L-7    L-7  L-8    L-8                               23 + 3   L-5      L-5    L-6    L-6  L-7    L-7                               ______________________________________                                    

                  TABLE XXXII                                                     ______________________________________                                        Meat Surface Color                                                            MA Storage                                                                              Days in                                                             Intervals,                                                                              Display                                                             32° F.                                                                           Case     Treatment Series                                           (Days)    at 32° F.                                                                       1       2   3     4   5     6                              ______________________________________                                         5        0        6.0     6.0 5.0   6.0 5.0   6.0                                      1        5.0     6.0 5.0   6.0 5.0   6.0                                      2        5.0     6.0 4.5   6.0 4.5   6.0                                      3        5.0     6.0 4.0   6.0 4.0   6.0                            11        0        3.0     6.0 3.0   6.0 4.0   6.0                                      1        3.0     6.0 3.0   6.0 4.0   6.0                                      2        3.0     6.0 3.0   6.0 4.0   6.0                                      3        2.0     6.0 2.0   6.0 3.0   6.0                            16        0        1.0     6.0 1.0   6.0 1.0   6.0                                      1        1.0     6.0 1.0   6.0 1.0   6.0                                      2        1.0     6.0 1.0   6.0 1.0   6.0                                      3        1.0     6.0 1.0   6.0 1.0   6.0                            23        0        1.0     6.0 1.0   6.0 1.0   6.0                                      1        1.0     6.0 1.0   6.0 1.0   6.0                                      2        1.0     6.0 1.0   6.0 1.0   6.0                                      3        1.0     6.0 1.0   6.0 1.0   6.0                            ______________________________________                                    

Lamb chops treated with the treating solution of the present invention,followed by packaging in a modified atmosphere were compared by a tastepanel with control chops which had not been treated with the treatingsolution. After cooking and dividing each lamb chop into two portions,the chops were tested by the panel of six testers after they had beenstored for various intervals. The chops in the several test lots wererated according to total flavor, texture, off-flavor of the lean meatand overall impression. The results of the taste panel testing are setforth in Table XXXIII.

                                      TABLE XXXIII                                __________________________________________________________________________    Taste Panel Testing                                                           MA Storage Plus                                                               Display Intervals                                                                      Total             Off Flavor                                                                          Overall                                      (Total Days)                                                                           Flavor                                                                              Texture                                                                             Juiciness                                                                           (Lean)                                                                              Impression                                   __________________________________________________________________________    5  Control                                                                             5.17 ± 0.41                                                                      3.83 ± 0.75                                                                      4.50 ± 0.84                                                                      1.33 ± 0.52                                                                      4.33 ± 0.52                                  Treated                                                                             4.83 ± 0.75                                                                      3.83 ± 0.75                                                                      4.00 ± 1.10                                                                      1.00 ± 0.00                                                                      4.17 ± 0.98                               8  Control                                                                             4.42 ± 1.56                                                                      4.58 ± 0.49                                                                      4.57 ± 0.52                                                                      1.33 ± 0.52                                                                      4.67 ± 0.98                                  Treated                                                                             5.17 ± 0.41                                                                      5.00 ± 0.89                                                                      4.83 ± 0.41                                                                      1.00 ± 0.00                                                                      5.00 ± 0.63                               14 Control                                                                             4.17 ± 0.98                                                                      4.00 ± 1.10                                                                      4.17 ± 0.98                                                                      1.83 ± 0.98                                                                      4.00 ± 1.10                                  Treated                                                                             5.17 ± 0.98                                                                      4.83 ± 0.98                                                                      5.00 ± 1.10                                                                      1.00 ± 0.00                                                                      5.17 ± 0.98                               19 Control                                                                             4.40 ± 0.55                                                                      4.60 ± 0.89                                                                      4.80 ± 0.84                                                                      2.00 ± 1.00                                                                      4.30 ± 0.67                                  Treated                                                                             5.00 ± 1.00                                                                      5.00 ± 1.22                                                                      5.20 ± 0.45                                                                      1.40 ± 0.89                                                                      4.80 ± 0.84                               26 Control                                                                             3.70 ± 0.67                                                                      3.60 ± 0.55                                                                      3.80 ± 0.84                                                                      2.00 ± 1.00                                                                      3.50 ± 0.71                                  Treated                                                                             4.80 ± 0.45                                                                      5.00 ± 0.71                                                                      4.90 ± 0.74                                                                      1.00 ± 0.00                                                                      4.80 ± 0.45                               __________________________________________________________________________     *Total Flavor/Texture/Juiciness/Overall Impression                            7 = Excellent                                                                 6 = Very good                                                                 5 = Good                                                                      4 = Fair                                                                      3 = Poor                                                                      2 = Very poor                                                                 1 = Extremely poor                                                            **Off Flavor                                                                  5 = Very strong off flavor                                                    4 = Strong off flavor                                                         3 = Moderate off flavor                                                       2 = Weak off flavor                                                           1 = Absent/no off flavor                                                 

The tests of the lamb chops can be summarized as leading to severalconclusions. Where modified atmosphere packaging of the chops is used,the microbiological shelf-life is extended to 26 days or longer.Pre-treatment with the three component aqueous treating solution waseffective in retarding oxidative rancidity and in maintaining the freshmeat color of the meat. The overall acceptable shelf-life of chopssubjected to treatment with the three component aqueous composition,coupled with packaging in a modified atmosphere, extended the overallacceptable shelf-life from 8 days, for the untreated control chops, to26 days for the treated chops. In untreated meat, oxidative rancidityand meat discoloration were accelerated when a modified atmosphere wasused for storage, as compared to air. In other words, the use of themodified atmosphere employed in the second, packaging step of thepresent invention had a deleterious effect on untreated meat, in thatoxidative rancidity and meat discoloration were accelerated.

Although a preferred embodiment of the invention has been hereindescribed in order to provide an adequate illustration of the principlesupon which the invention is based, it will be understood that variouschanges and innovations can be effected in the described procedureswithout departure from these principles. Changes and modifications ofthis type are therefore deemed to be circumscribed by the spirit andscope of the invention, except as the same may be necessarily limited bythe appended claims, or reasonable equivalents thereof.

What is claimed is:
 1. A process for packing fresh meat cutscomprising:treating the fresh meat cuts by contacting the fresh meatcuts with an aqueous solution containing (a) a phosphate compoundselected from the ground consisting of the alkali metal orthophosphates,alkali metal pyrophosphates, alkali metal tripolyphosphates and alkalimetal hexametaphosphates; (b) a reducing compound selected from thegroup consisting of ascorbic acid, isoascorbic acid, the alkali metalsalts of said acids, and reductic acid, and (c) a sequestering agentselected from the group consisting of citric acid, tartaric acid,ethylenediaminetetracetic acid, and the sodium and potassium salts ofsuch acids, so as to place in the so treated meat, from about 0.1 weightpercent to about 2.0 weight percent of the phosphate compound, fromabout 0.01 weight percent to about 0.3 weight percent of said reducingcompound, and from about 0.01 weight percent to about 0.3 weight percentof said sequestering agent, all based on the total weight of the freshmeat cut so treated by contacting; then packaging the treated fresh meatcuts in a gaseous mixture which comprises from about 2 percent to about25 oxygen, and from about 20 percent to about 80 percent carbon dioxide,with the balance being nitrogen, whereby the properties of the thustreated and packaged meat are improved and will remain good for anextended period of time of up to at least 21 days in said controlledgaseous atmosphere, and whereby the microbial shelf life of the meat iscaused to be at least as long as the color shelf life of the meat.
 2. Aprocess as defined in claim 1 wherein from about 0.2 weight percent toabout 0.5 weight percent of said phosphate compound, from about 0.02weight percent to about 0.05 weight percent of said reducing compound,and from about 0.01 weight percent to about 0.05 weight percent of saidsequestering agent are placed in the meat by said contacting step.
 3. Aprocess as defined in claim 2 wherein the sequestering agent utilized iscitric acid.
 4. A process as defined in claim 1 wherein the gaseousmixture contains about 13 percent oxygen and about 50 percent carbondioxide.
 5. A process as defined in claim 1 wherein said aqueoussolution is placed in the meat by injection.
 6. A process as defined inclaim 1 wherein said aqueous solution is placed in the meat by immersingthe meat in the aqueous solution and marinating the meat.
 7. A processas defined in claim 1 wherein said aqueous solution is placed in themeat by spraying the meat with the aqueous solution.
 8. A process asdefined in claim 1 and further characterized by the additional step ofretaining the packaged meat at a temperature of 34±2° F. during theshipment and storage thereof.
 9. A process as defined in claim 1 whereinsaid buffer solution has a pH of from about 5.0 to about 8.0.